What are Srinivasa Ramanujan’s major contributions to mathematics?

Great mathematician Srinivasa Ramanujan's main contributions in mathematics lie in the fields of analysis, infinite series, number theory and game theory. Ramanujan found a formula for infinite series for pi, which forms the basis of many algorithms used today. He elaborated on the mock theta function. Ramanujan Number (1729), circle method, and theta function are some of his other contributions.